It is possible for a recent digital camera to take a movie also, but, although high image quality is realized, wind noise is likely to mix into a sound at the time of video taking. It is possible to attach a wind-shielding sponge or the like to a video camera etc. capable of mounting an external microphone, but, many digital cameras record sound with an internal microphone. Hence, a technique to suppress wind noise by signal processing is used conventionally.
Wind noise tends to concentrate in a low-frequency band and there is a known technique to suppress the region with a high-pass filter.
Further, a technique to divide an input signal into bands and to detect wind noise from the autocorrelation between the bands is also known. In this technique, by reducing an input signal on the low-frequency band side where wind noise is dominant more than an input signal on the high-frequency band side, the audio signal included mostly on the high-frequency band side is prevented from being lost.
Furthermore, there used to be a technique to detect a wind noise component from a difference or a correlation value between 2-channel signals by utilizing the fact that the wind noise has little correlation between channels, in the 2-channel signals recorded with two microphones. For example, the following literature describes such conventional techniques:
Japanese Laid-Open Patent Publication No. 2001-352594
Japanese Patent No. 3186892
Japanese Laid-Open Patent Publication No. 2009-55583
There is a case where an audio signal, not noise, is included also on the low-frequency band side in which wind noise is included, and therefore, it used to be difficult to suppress wind noise without losing the naturalness of sound.